The Helicopter Speed Limit - Helicopter Physics Series - #7 - Smarter Every Day 51 | Summary and Q&A

TL;DR

Helicopters have a speed limit due to the dissymmetry of rotor flight, which affects the lift generated by the blades on each side.

Key Insights

• ✈️ The dissymmetry of rotor flight is caused by the difference in speed and relative air velocity between the advancing and retreating blades.
• 🫢 Exceeding the speed limit of a helicopter can lead to shock waves and damage the rotor system.
• 😘 The retreating blade in rotor flight requires increased pitch to compensate for the lower airspeed and maintain lift.
• 🥺 A retreating blade stall, caused by excessive speed and pitch, can lead to a decrease in lift and potential control issues.
• 🤳 Gyroscopic procession helps maintain stability and self-corrects the helicopter's flight attitude during a retreating blade stall.
• 💨 The Chinook helicopter is the fastest in the US Army inventory, based on the information provided.
• 🧑‍✈️ The dissymmetry of rotor flight and its effects on helicopter speed are important considerations for pilots and engineers.

Transcript

Helicopters have a speed limit that has nothing to do with laws. Well, unless you count the laws of physics. Hey it's me Destin. Welcome back to Smarter Every Day. The show where we do science. So today I'm gonna explain to you something pretty interesting about the dissymmetry of rotor flight. But before we get too serious, let's just have a lit... Read More

Questions & Answers

Q: What is the dissymmetry of rotor flight in helicopters?

The dissymmetry of rotor flight refers to the unequal behavior of the advancing and retreating blades on a helicopter's rotor, affecting the lift generated on each side.

Q: How does the speed of a helicopter impact its rotor and lift?

If a helicopter exceeds a certain speed, shock waves can form and cause damage to the rotor. Additionally, excessive speed can lead to a retreating blade stall, reducing lift and potentially causing control issues.

Q: How does the dissymmetry of rotor flight self-correct excessive speed?

Due to gyroscopic procession, a dissymmetry of lift between the left and right sides of the helicopter causes the aircraft to pitch rather than roll. This self-correction helps slow down the helicopter when it experiences a retreating blade stall.

Q: Which helicopter is the fastest in the US Army inventory?

The Chinook helicopter is the fastest in the US Army inventory according to the video.

Summary & Key Takeaways

• The dissymmetry of rotor flight occurs when one side of the helicopter's rotor has a smaller radius of curvature than the other side.

• The advancing blade on the helicopter moves faster relative to the air, while the retreating blade has a lower relative velocity.

• If a helicopter flies too fast, it can create shock waves and damage the rotor, and excessive pitch on the retreating side can lead to a retreating blade stall.